PROJECT SUMMARY/ABSTRACT: The goals of this grant application are to develop the PediCODE Consortium and Biorepository and to identify the monogenic causes of COngenital Diarrhea and Enteropathy (CODE). The CODE disorders are rare monogenic disorders that are under-researched and associated with an enormous management costs and adverse life-long outcomes. We will characterize their clinical and pathophysiological features of these disorders and develop a clinical database and biorepository of disease-specific cells, tissues, and other primary patient materials. We anticipate that through these efforts we will identify novel genes implicated in CODE, while we establish a unique resource enabling mechanistic studies on both known and unknown causal CODE genes. To achieve these goals, we have assembled a multidisciplinary group of Physician-Scientists that have interest and experience in cell biology and genetic disorders that result in diarrhea. Our goals will be accomplished with three aims. We will initially develop a prospective cohort and registry of affected CODE children and follow their clinical course. We will also perform or gather data of whole exome sequencing from the majority of these patients, and we will develop a CODE tissue histopathology atlas from biopsy samples. The consortium will also collect cell samples (intestinal epithelium, blood and skin fibroblasts), as well as serum and stool samples. We will investigate the enteroids generated from the biopsy samples, and/or generate intestinal organoids from pluripotent stem cells, and these will be characterized and validated by immunostaining and RNA sequencing. We will then utilize existing and develop novel technologies to characterize and investigate the epithelial phenotypes of CODE disorders using polarized cells, patient-derived enteroids and disease-specific zebrafish models. Finally, we will seek to characterize functional alterations in a minimum of 4 novel disorders from our cohort of CODE patients. This in-depth analysis will include functional characterization using intestinal organoids where we will assess barrier formation, active ion and water transport, and vesicular trafficking/protein sorting. We anticipate that the PediCODE Consortium and Biorepository will be a rich resource for patients and their families, clinicians and bench researchers. We anticipate that these efforts will expand our understanding of CODE disorders and identify novel approaches for improving clinical symptoms of affected children.